diff --git a/src/GetResponseAPI3.class.php b/src/GetResponseAPI3.class.php
index 2782e2f..fb4c894 100644
--- a/src/GetResponseAPI3.class.php
+++ b/src/GetResponseAPI3.class.php
@@ -12,395 +12,397 @@
 class GetResponse
 {
 
-    private $api_key;
-    private $api_url = 'https://api.getresponse.com/v3';
-    private $timeout = 8;
-    public $http_status;
-
-    /**
-     * X-Domain header value if empty header will be not provided
-     * @var string|null
-     */
-    private $enterprise_domain = null;
-
-    /**
-     * X-APP-ID header value if empty header will be not provided
-     * @var string|null
-     */
-    private $app_id = null;
-
-    /**
-     * Set api key and optionally API endpoint
-     * @param      $api_key
-     * @param null $api_url
-     */
-    public function __construct($api_key, $api_url = null)
-    {
-        $this->api_key = $api_key;
-
-        if (!empty($api_url)) {
-            $this->api_url = $api_url;
-        }
-    }
-
-    /**
-     * We can modify internal settings
-     * @param $key
-     * @param $value
-     */
-    function __set($key, $value)
-    {
-        $this->{$key} = $value;
-    }
-
-    /**
-     * get account details
-     *
-     * @return mixed
-     */
-    public function accounts()
-    {
-        return $this->call('accounts');
-    }
-
-    /**
-     * @return mixed
-     */
-    public function ping()
-    {
-        return $this->accounts();
-    }
-
-    /**
-     * Return all campaigns
-     * @return mixed
-     */
-    public function getCampaigns()
-    {
-        return $this->call('campaigns');
-    }
-
-    /**
-     * get single campaign
-     * @param string $campaign_id retrieved using API
-     * @return mixed
-     */
-    public function getCampaign($campaign_id)
-    {
-        return $this->call('campaigns/' . $campaign_id);
-    }
-
-    /**
-     * adding campaign
-     * @param $params
-     * @return mixed
-     */
-    public function createCampaign($params)
-    {
-        return $this->call('campaigns', 'POST', $params);
-    }
-
-    /**
-     * list all RSS newsletters
-     * @return mixed
-     */
-    public function getRSSNewsletters()
-    {
-        $this->call('rss-newsletters', 'GET', null);
-    }
-
-    /**
-     * send one newsletter
-     *
-     * @param $params
-     * @return mixed
-     */
-    public function sendNewsletter($params)
-    {
-        return $this->call('newsletters', 'POST', $params);
-    }
-
-    /**
-     * @param $params
-     * @return mixed
-     */
-    public function sendDraftNewsletter($params)
-    {
-        return $this->call('newsletters/send-draft', 'POST', $params);
-    }
-
-    /**
-     * add single contact into your campaign
-     *
-     * @param $params
-     * @return mixed
-     */
-    public function addContact($params)
-    {
-        return $this->call('contacts', 'POST', $params);
-    }
-
-    /**
-     * retrieving contact by id
-     *
-     * @param string $contact_id - contact id obtained by API
-     * @return mixed
-     */
-    public function getContact($contact_id)
-    {
-        return $this->call('contacts/' . $contact_id);
-    }
-
-
-    /**
-     * search contacts
-     *
-     * @param $params
-     * @return mixed
-     */
-    public function searchContacts($params = null)
-    {
-        return $this->call('search-contacts?' . $this->setParams($params));
-    }
-
-    /**
-     * retrieve segment
-     *
-     * @param $id
-     * @return mixed
-     */
-    public function getContactsSearch($id)
-    {
-        return $this->call('search-contacts/' . $id);
-    }
-
-    /**
-     * add contacts search
-     *
-     * @param $params
-     * @return mixed
-     */
-    public function addContactsSearch($params)
-    {
-        return $this->call('search-contacts/', 'POST', $params);
-    }
-
-    /**
-     * add contacts search
-     *
-     * @param $id
-     * @return mixed
-     */
-    public function deleteContactsSearch($id)
-    {
-        return $this->call('search-contacts/' . $id, 'DELETE');
-    }
-
-    /**
-     * get contact activities
-     * @param $contact_id
-     * @return mixed
-     */
-    public function getContactActivities($contact_id)
-    {
-        return $this->call('contacts/' . $contact_id . '/activities');
-    }
-
-    /**
-     * retrieving contact by params
-     * @param array $params
-     *
-     * @return mixed
-     */
-    public function getContacts($params = array())
-    {
-        return $this->call('contacts?' . $this->setParams($params));
-    }
-
-    /**
-     * updating any fields of your subscriber (without email of course)
-     * @param       $contact_id
-     * @param array $params
-     *
-     * @return mixed
-     */
-    public function updateContact($contact_id, $params = array())
-    {
-        return $this->call('contacts/' . $contact_id, 'POST', $params);
-    }
-
-    /**
-     * drop single user by ID
-     *
-     * @param string $contact_id - obtained by API
-     * @return mixed
-     */
-    public function deleteContact($contact_id)
-    {
-        return $this->call('contacts/' . $contact_id, 'DELETE');
-    }
-
-    /**
-     * retrieve account custom fields
-     * @param array $params
-     *
-     * @return mixed
-     */
-    public function getCustomFields($params = array())
-    {
-        return $this->call('custom-fields?' . $this->setParams($params));
-    }
-
-    /**
-     * add custom field
-     *
-     * @param $params
-     * @return mixed
-     */
-    public function setCustomField($params)
-    {
-        return $this->call('custom-fields', 'POST', $params);
-    }
-
-    /**
-     * retrieve single custom field
-     *
-     * @param string $cs_id obtained by API
-     * @return mixed
-     */
-    public function getCustomField($custom_id)
-    {
-        return $this->call('custom-fields/' . $custom_id, 'GET');
-    }
-
-    /**
-     * retrieving billing information
-     *
-     * @return mixed
-     */
-    public function getBillingInfo()
-    {
-        return $this->call('accounts/billing');
-    }
-
-    /**
-     * get single web form
-     *
-     * @param int $w_id
-     * @return mixed
-     */
-    public function getWebForm($w_id)
-    {
-        return $this->call('webforms/' . $w_id);
-    }
-
-    /**
-     * retrieve all webforms
-     * @param array $params
-     *
-     * @return mixed
-     */
-    public function getWebForms($params = array())
-    {
-        return $this->call('webforms?' . $this->setParams($params));
-    }
-
-    /**
-     * get single form
-     *
-     * @param int $form_id
-     * @return mixed
-     */
-    public function getForm($form_id)
-    {
-        return $this->call('forms/' . $form_id);
-    }
-
-    /**
-     * retrieve all forms
-     * @param array $params
-     *
-     * @return mixed
-     */
-    public function getForms($params = array())
-    {
-        return $this->call('forms?' . $this->setParams($params));
-    }
-
-    /**
-     * Curl run request
-     *
-     * @param null $api_method
-     * @param string $http_method
-     * @param array $params
-     * @return mixed
-     * @throws Exception
-     */
-    private function call($api_method = null, $http_method = 'GET', $params = array())
-    {
-        if (empty($api_method)) {
-            return (object)array(
-                'httpStatus' => '400',
-                'code' => '1010',
-                'codeDescription' => 'Error in external resources',
-                'message' => 'Invalid api method'
-            );
-        }
-
-        $params = json_encode($params);
-        $url = $this->api_url . '/' . $api_method;
-
-        $options = array(
-            CURLOPT_URL => $url,
-            CURLOPT_ENCODING => 'gzip,deflate',
-            CURLOPT_FRESH_CONNECT => 1,
-            CURLOPT_RETURNTRANSFER => 1,
-            CURLOPT_TIMEOUT => $this->timeout,
-            CURLOPT_HEADER => false,
-            CURLOPT_USERAGENT => 'PHP GetResponse client 0.0.2',
-            CURLOPT_HTTPHEADER => array('X-Auth-Token: api-key ' . $this->api_key, 'Content-Type: application/json')
-        );
-
-        if (!empty($this->enterprise_domain)) {
-            $options[CURLOPT_HTTPHEADER][] = 'X-Domain: ' . $this->enterprise_domain;
-        }
-
-        if (!empty($this->app_id)) {
-            $options[CURLOPT_HTTPHEADER][] = 'X-APP-ID: ' . $this->app_id;
-        }
-
-        if ($http_method == 'POST') {
-            $options[CURLOPT_POST] = 1;
-            $options[CURLOPT_POSTFIELDS] = $params;
-        } else if ($http_method == 'DELETE') {
-            $options[CURLOPT_CUSTOMREQUEST] = 'DELETE';
-        }
-
-        $curl = curl_init();
-        curl_setopt_array($curl, $options);
-
-        $response = json_decode(curl_exec($curl));
-
-        $this->http_status = curl_getinfo($curl, CURLINFO_HTTP_CODE);
-
-        curl_close($curl);
-        return (object)$response;
-    }
-
-    /**
-     * @param array $params
-     *
-     * @return string
-     */
-    private function setParams($params = array())
-    {
-        $result = array();
-        if (is_array($params)) {
-            foreach ($params as $key => $value) {
-                $result[$key] = $value;
-            }
-        }
-        return http_build_query($result);
-    }
-
-}
\ No newline at end of file
+	private $api_key;
+	private $api_url = 'https://api.getresponse.com/v3';
+	private $timeout = 8;
+	private $returnAssociative = false;
+	public $http_status;
+
+	/**
+	 * X-Domain header value if empty header will be not provided
+	 * @var string|null
+	 */
+	private $enterprise_domain = null;
+
+	/**
+	 * X-APP-ID header value if empty header will be not provided
+	 * @var string|null
+	 */
+	private $app_id = null;
+
+	/**
+	 * Set api key and optionally API endpoint
+	 * @param      $api_key
+	 * @param null $api_url
+	 */
+	public function __construct($api_key, $api_url = null)
+	{
+		$this->api_key = $api_key;
+
+		if (!empty($api_url)) {
+			$this->api_url = $api_url;
+		}
+	}
+
+	/**
+	 * We can modify internal settings
+	 * @param $key
+	 * @param $value
+	 */
+	function __set($key, $value)
+	{
+		$this->{$key} = $value;
+	}
+
+	/**
+	 * get account details
+	 *
+	 * @return mixed
+	 */
+	public function accounts()
+	{
+		return $this->call('accounts');
+	}
+
+	/**
+	 * @return mixed
+	 */
+	public function ping()
+	{
+		return $this->accounts();
+	}
+
+	/**
+	 * Return campaigns
+	 * @param array $params
+	 * @return mixed
+	 */
+	public function getCampaigns($params = array())
+	{
+		return $this->call('campaigns', 'GET', $params);
+	}
+
+	/**
+	 * get single campaign
+	 * @param string $campaign_id retrieved using API
+	 * @param array $params fields
+	 * @return mixed
+	 */
+	public function getCampaign($campaign_id, $params = array())
+	{
+		return $this->call('campaigns/' . $campaign_id, 'GET', $params);
+	}
+
+	/**
+	 * retrieving contacts in campaign by params
+	 * @param string $campaign_id
+	 * @param array $params
+	 * @return mixed
+	 */
+	public function getCampaignContacts($campaign_id, $params = array())
+	{
+		return $this->call('campaigns/'.$campaign_id.'/contacts', 'GET', $params);
+	}
+
+	/**
+	 * adding campaign
+	 * @param $params
+	 * @return mixed
+	 */
+	public function createCampaign($params)
+	{
+		return $this->call('campaigns', 'POST', $params);
+	}
+
+	/**
+	 * list all RSS newsletters
+	 * @return mixed
+	 */
+	public function getRSSNewsletters()
+	{
+		$this->call('rss-newsletters');
+	}
+
+	/**
+	 * send one newsletter
+	 *
+	 * @param $params
+	 * @return mixed
+	 */
+	public function sendNewsletter($params)
+	{
+		return $this->call('newsletters', 'POST', $params);
+	}
+
+	/**
+	 * @param $params
+	 * @return mixed
+	 */
+	public function sendDraftNewsletter($params)
+	{
+		return $this->call('newsletters/send-draft', 'POST', $params);
+	}
+
+	/**
+	 * add single contact into your campaign
+	 *
+	 * @param $params
+	 * @return mixed
+	 */
+	public function addContact($params)
+	{
+		return $this->call('contacts', 'POST', $params);
+	}
+
+	/**
+	 * retrieving contact by id
+	 *
+	 * @param string $contact_id - contact id obtained by API
+	 * @return mixed
+	 */
+	public function getContact($contact_id)
+	{
+		return $this->call('contacts/' . $contact_id);
+	}
+
+
+	/**
+	 * search contacts
+	 *
+	 * @param $params
+	 * @return mixed
+	 */
+	public function searchContacts($params = array())
+	{
+		return $this->call('search-contacts', 'GET', $params);
+	}
+
+	/**
+	 * retrieve segment
+	 *
+	 * @param $id
+	 * @return mixed
+	 */
+	public function getContactsSearch($id)
+	{
+		return $this->call('search-contacts/' . $id);
+	}
+
+	/**
+	 * add contacts search
+	 *
+	 * @param $params
+	 * @return mixed
+	 */
+	public function addContactsSearch($params)
+	{
+		return $this->call('search-contacts/', 'POST', $params);
+	}
+
+	/**
+	 * add contacts search
+	 *
+	 * @param $id
+	 * @return mixed
+	 */
+	public function deleteContactsSearch($id)
+	{
+		return $this->call('search-contacts/' . $id, 'DELETE');
+	}
+
+	/**
+	 * get contact activities
+	 * @param $contact_id
+	 * @return mixed
+	 */
+	public function getContactActivities($contact_id)
+	{
+		return $this->call('contacts/' . $contact_id . '/activities');
+	}
+
+	/**
+	 * retrieving contact by params
+	 * @param array $params
+	 * @return mixed
+	 */
+	public function getContacts($params = array())
+	{
+		return $this->call('contacts', 'GET', $params);
+	}
+
+	/**
+	 * updating any fields of your subscriber (without email of course)
+	 * @param       $contact_id
+	 * @param array $params
+	 *
+	 * @return mixed
+	 */
+	public function updateContact($contact_id, $params = array())
+	{
+		return $this->call('contacts/' . $contact_id, 'POST', $params);
+	}
+
+	/**
+	 * drop single user by ID
+	 *
+	 * @param string $contact_id - obtained by API
+	 * @return mixed
+	 */
+	public function deleteContact($contact_id)
+	{
+		return $this->call('contacts/' . $contact_id, 'DELETE');
+	}
+
+	/**
+	 * retrieve account custom fields
+	 * @param array $params
+	 *
+	 * @return mixed
+	 */
+	public function getCustomFields($params = array())
+	{
+		return $this->call('custom-fields', 'GET', $params);
+	}
+
+	/**
+	 * add custom field
+	 *
+	 * @param $params
+	 * @return mixed
+	 */
+	public function setCustomField($params)
+	{
+		return $this->call('custom-fields', 'POST', $params);
+	}
+
+	/**
+	 * retrieve single custom field
+	 *
+	 * @param string $cs_id obtained by API
+	 * @return mixed
+	 */
+	public function getCustomField($custom_id)
+	{
+		return $this->call('custom-fields/' . $custom_id, 'GET');
+	}
+
+	/**
+	 * retrieving billing information
+	 *
+	 * @return mixed
+	 */
+	public function getBillingInfo()
+	{
+		return $this->call('accounts/billing');
+	}
+
+	/**
+	 * get single web form
+	 *
+	 * @param int $w_id
+	 * @return mixed
+	 */
+	public function getWebForm($w_id)
+	{
+		return $this->call('webforms/' . $w_id);
+	}
+
+	/**
+	 * retrieve all webforms
+	 * @param array $params
+	 *
+	 * @return mixed
+	 */
+	public function getWebForms($params = array())
+	{
+		return $this->call('webforms', 'GET', $params);
+	}
+
+	/**
+	 * get single form
+	 *
+	 * @param int $form_id
+	 * @return mixed
+	 */
+	public function getForm($form_id)
+	{
+		return $this->call('forms/' . $form_id);
+	}
+
+	/**
+	 * retrieve all forms
+	 * @param array $params
+	 *
+	 * @return mixed
+	 */
+	public function getForms($params = array())
+	{
+		return $this->call('forms', 'GET', $params);
+	}
+
+	/**
+	 * Curl run request
+	 *
+	 * @param null $api_method
+	 * @param string $http_method
+	 * @param array $params
+	 * @return mixed
+	 * @throws Exception
+	 */
+	private function call($api_method = null, $http_method = 'GET', $params = array())
+	{
+		if (empty($api_method)) {
+			return (object)array(
+				'httpStatus' => '400',
+				'code' => '1010',
+				'codeDescription' => 'Error in external resources',
+				'message' => 'Invalid api method'
+			);
+		}
+
+		$url = $this->api_url . '/' . $api_method;
+
+		if ($http_method == 'GET' && $params) {
+			$url .= '?'.http_build_query($params);
+		}
+
+		$options = array(
+			CURLOPT_URL => $url,
+			CURLOPT_ENCODING => 'gzip,deflate',
+			CURLOPT_FRESH_CONNECT => 1,
+			CURLOPT_RETURNTRANSFER => 1,
+			CURLOPT_TIMEOUT => $this->timeout,
+			CURLOPT_HEADER => false,
+			CURLOPT_USERAGENT => 'PHP GetResponse client 0.0.2',
+			CURLOPT_HTTPHEADER => array('X-Auth-Token: api-key ' . $this->api_key, 'Content-Type: application/json')
+		);
+
+		if (!empty($this->enterprise_domain)) {
+			$options[CURLOPT_HTTPHEADER][] = 'X-Domain: ' . $this->enterprise_domain;
+		}
+
+		if (!empty($this->app_id)) {
+			$options[CURLOPT_HTTPHEADER][] = 'X-APP-ID: ' . $this->app_id;
+		}
+
+		if ($http_method == 'POST') {
+			$params = json_encode($params);
+			$options[CURLOPT_POST] = 1;
+			$options[CURLOPT_POSTFIELDS] = $params;
+		} else if ($http_method == 'DELETE') {
+			$options[CURLOPT_CUSTOMREQUEST] = 'DELETE';
+		}
+
+		$curl = curl_init();
+		curl_setopt_array($curl, $options);
+
+		$response = json_decode(curl_exec($curl), $this->returnAssociative);
+
+		$this->http_status = curl_getinfo($curl, CURLINFO_HTTP_CODE);
+
+		curl_close($curl);
+
+		return $response;
+	}
+
+}